The FDA said it was investigating complaints about the patch, sold under the brand name Zecuity. It delivers the migraine drug sumatriptan through the skin, using an electric current generated by the batteries.

Some patients can get a blistering allergic reaction to it but the FDA said it had received reports that the patch could also cause serious burns.

eva Pharmaceuticals USA, Inc.

“A large number of patients have reported they experienced burns or scars on the skin where the patch was worn. The reports included descriptions of severe redness, pain, skin discoloration, blistering, and cracked skin,” the FDA said in a statement.

“We are investigating the cause and extent of these serious side effects and will update the public with new information when our review is complete,” it added.

“Patients who experience moderate to severe pain at the Zecuity patch site should immediately remove it to avoid possible burns or scarring, regardless of how long the patch has been worn, and contact your health care professional. Do not bathe, shower, or swim while wearing the patch,” the FDA advised.

“Health care professionals should advise patients who complain of moderate to severe pain at the application site to remove the Zecuity patch immediately. Consider a different formulation of sumatriptan or switch these patients to an alternative migraine medicine.”

The patch, which has been on the market since September, can be wrapped around the arm or the thigh. It’s a one-time use product and people are supposed to take it off after four hours.

The company warns of mild effects.

"The most common side effects of Zecuity include pain, tingling, itching, warmth, discomfort or a change in the skin color at the application site of Zecuity," it says.

"Most people have some skin redness after removal of Zecuity. This redness will usually go away in 24 hours. Tell your healthcare provider if you have any side effect that bothers you or that does not go away."

More than 36 million Americans suffer from migraines, according to the American Headache Society. Of these, about 4 million have chronic migraine and suffer headaches for 10 to 14 days a month.

Migraines are not ordinary headaches and while some people are helped by over-the-counter drugs such as ibuprofen, others turn to stronger prescription drugs such as sumatriptan and ergotamine drugs, which constrict the blood vessels in the brain.